Revert "MEDIUM: queue: determine in process_srv_queue() if the proxy is usable"

This reverts commit de814dd4228fa5e528d9ac1f0e1c4c7325ee52d3.

The recent changes since 5304669e1 MEDIUM: queue: make
pendconn_process_next_strm() only return the pendconn opened a tiny race
condition between stream_free() and process_srv_queue(), as the pendconn
is accessed outside of the lock, possibly while it's being freed. A
different approach is required.

diff --git a/src/queue.c b/src/queue.c
index 5c9db172544d8e328bbe71731787c8ada8c55685..20880a2390d9b1d742ca45e2423d781ce1c2e66e 100644 (file)
--- a/src/queue.c
+++ b/src/queue.c
@@ -253,28 +253,34 @@ static struct pendconn *pendconn_first(struct eb_root *pendconns)
  * immediately marked as "assigned", and both its <srv> and <srv_conn> are set
  * to <srv>.
  *
- * The proxy's queue will be consulted only if px_ok is non-zero.
- *
  * This function must only be called if the server queue _AND_ the proxy queue
- * are locked (if pk_ok is set). Today it is only called by process_srv_queue.
+ * are locked. Today it is only called by process_srv_queue.
  *
  * The function returns the dequeued pendconn on success or NULL if none is
  * available. It's up to the caller to add the corresponding stream to the
  * server's list, to update the LB algo, update ->served, and to wake up the
  * stream's task.
  */
-static struct pendconn *pendconn_process_next_strm(struct server *srv, struct proxy *px, int px_ok)
+static struct pendconn *pendconn_process_next_strm(struct server *srv, struct proxy *px)
 {
        struct pendconn *p = NULL;
        struct pendconn *pp = NULL;
+       struct server   *rsrv;
        u32 pkey, ppkey;
 
+       rsrv = srv->track;
+       if (!rsrv)
+               rsrv = srv;
+
        p = NULL;
        if (srv->queue.length)
                p = pendconn_first(&srv->queue.head);
 
        pp = NULL;
-       if (px_ok && px->queue.length)
+       if (srv_currently_usable(rsrv) && px->queue.length &&
+           (!(srv->flags & SRV_F_BACKUP) ||
+            (!px->srv_act &&
+             (srv == px->lbprm.fbck || (px->options & PR_O_USE_ALL_BK)))))
                pp = pendconn_first(&px->queue.head);
 
        if (!p && !pp)
@@ -329,19 +335,9 @@ static struct pendconn *pendconn_process_next_strm(struct server *srv, struct pr
  */
 void process_srv_queue(struct server *s)
 {
-       struct server *ref = s->track ? s->track : s;
        struct proxy  *p = s->proxy;
        int done = 0;
        int maxconn;
-       int px_ok;
-
-       /* if a server is not usable or backup and must not be used
-        * to dequeue backend requests.
-        */
-       px_ok = srv_currently_usable(ref) &&
-               (!(s->flags & SRV_F_BACKUP) ||
-                (!p->srv_act &&
-                 (s == p->lbprm.fbck || (p->options & PR_O_USE_ALL_BK))));
 
        maxconn = srv_dynamic_maxconn(s);
        while (s->served < maxconn) {
@@ -350,7 +346,7 @@ void process_srv_queue(struct server *s)
                HA_SPIN_LOCK(QUEUE_LOCK, &s->queue.lock);
                HA_SPIN_LOCK(QUEUE_LOCK, &p->queue.lock);
 
-               pc = pendconn_process_next_strm(s, p, px_ok);
+               pc = pendconn_process_next_strm(s, p);
 
                HA_SPIN_UNLOCK(QUEUE_LOCK, &p->queue.lock);
                HA_SPIN_UNLOCK(QUEUE_LOCK, &s->queue.lock);